Bono's friends trashed his car to make him "lighten up".

The U2 frontman thinks the band got "too straight" following their initial surge to fame in the 1980s and his old pals decided to teach him a lesson in order to bring him back to reality.

He said: "The band just got too straight in the 80s.

"I mean, we were wrestling with some pretty big questions but I kind of lost touch with my friends. I remember one night at home in Dublin, my father woke me up and said, 'There's someone trying to steal your car.'

"He had an iron bar in his hand. I looked out the window... I had this tiny little Fiat Bambino. They'd wrapped the entire car in toilet roll and were smashing eggs on it. I didn't see it at the time but it was my mates saying, 'You need to lighten up.' "

The 'One' hitmakers also admitted the period in the career around the time of their 1991 album 'Achtung Baby' was "challenging".

The Edge told Q magazine: "It was a very sobering, challenging period for us - very uncomfortable.

"It was at the end of my marriage. I'd moved in with Adam for a while. I threw myself into work and I guess that's how I got through and maybe why the album is as dark as it is."